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MG MGB
The MGB is a sports car launched by MG Cars in May 1962 to replace the MGA. Introduced as a four-cylinder roadster, a coupé with 2+2 seating was added in 1965. The six-cylinder MGC debuted in 1967; a later derivative fitted with the Buick-based Rover V8 was made from 1973 to 1976. MGB/MGC production continued until October 1980 variously by the British Motor Corporation and its successors, British Motor Holdings and British Leyland Motor Corporation. History In structure the MGB was a radically, modern design in 1962, utilizing a monocoque structure instead of the traditional body-on-frame construction used on both the MGA and MG T-types and the MGB's rival, the Triumph TR series. However components such as brakes and suspension were developments of the earlier 1955 MGA with the B-Series engine having its origins in 1947. The lightweight design reduced manufacturing costs while adding to overall vehicle strength. Wind-up windows were standard, and a comfortable driver's compartment offered plenty of legroom. A parcel shelf was fitted behind the seats. The MGB's performance was considered brisk at the time of its introduction, with a 0–60 mph (96 km/h) time of just over 11 seconds, aided by the relatively light weight of the car. Handling was one of the MGB's strong points. The 3-bearing 1798 cc B-Series engine produced 95 hp (71 kW) at 5,400 rpm. The engine was upgraded in October 1964 to a five-bearing crankshaft in an effort to improve reliability. A majority of MGBs were exported to United States. In 1974, as US air pollution emission standards became more rigorous, US-market MGBs were de-tuned for compliance. As well as a marked reduction in performance, the MGB gained an inch (25 mm) in ride height and the distinctive rubber bumpers which came to replace the chrome for all markets. The MGB was one of the first cars to feature controlled crumple zones designed to protect the driver and passenger in a 30 mph (48 km/h) impact with an immovable barrier (200 ton). Combined production volume of MGB, MGC and MGB GT V8 models was 523,836 cars. A very limited-production "revival" model with only 2,000 units made, called RV8 was produced by Rover in the 1990s. Despite the similarity in appearance to the roadster, the RV8 had less than 5 percent parts interchangeability with the original car. Drivetrain Engine: All MGBs (except the V8 version) utilized the BMC B-Series engine. This engine was essentially an enlarged version of that used in the MGA with displacement being increased from 1622 cc to 1798 cc. The earlier cars used a three main bearing crankshaft until mid-1965, when a five-bearing crankshaft design was introduced. Horsepower was rated at 95 bhp on both 3 main bearing and earlier 5-bearing cars with peak power coming at 5400 rpm with a 6000 rpm redline. Torque output on all MGB is good with a peak of Fuel consumption was around 25mpg .. US specification cars saw power fall in 1968 with the introduction of emission standards and the use of air or smog pumps. In 1971 UK spec cars still had at 5,500 rpm, with torque at 2500 rpm. By 1973 it was ; by 1974 it was 87, with torque; by 1975 it was 85 with . Some California specification cars produced only around by the late 1970s. The compression ratio was also reduced from 9 to 1 to 8:1 on US spec cars in 1972. Carburation: All MGBs from 1963 to 1974 used twin SU carburettors. US spec cars from 1975 used a single Stromberg carburettor mounted on a combination intake–exhaust manifold. This greatly reduced power as well as creating longevity problems as the (adjacent) catalytic converter tended to crack the intake–exhaust manifold. All MGBs used a SU-built electronic fuel pump. Gearbox:: All MGBs from 1962 to 1967 used a four-speed manual gearbox with a non-synchromesh, straight-cut first gear. Optional overdrive was available.. This gearbox was based on that used in the MGA with some minor upgrades to cope with the additional output of the larger MGB engine. In 1968 the early gearbox was replaced by a full synchromesh unit based on the MGC gearbox. This unit was designed to handle the 150 hp 3-litre engine of the MGC and was thus over-engineered when mated with the standard MGB B-Series engine. In fact, the same transmission was even used in the 3.5-litre V-8 version of the MGB-GT-V8. An automatic three-speed transmission was also offered as a factory option but proved to be fairly unpopular. Electrically engaged overdrive gearboxes were an available option on all MGBs. The overdrive unit was operational in third and fourth gears but the overall ratio in third gear overdrive was roughly the same as fourth gear direct. Later cars allowed the overdrive to operate only in fourth gear. The overdrive unit was engaged by a toggle switch located on the dash on 1963–1974 cars and on a gear lever mounted switch on later cars. Overdrives were fitted to less than 20% of all MGBs, making it a very desirable feature. Rear axle: Early MGBs used the "banjo" type differential carried over from the MGA with the rear axle ratio reduced from the MGA's 4.1 (or 4.3) to 3.9 to 1. (Compensating for the reduction from 15 inch to wheels.) MGB GTs first began using a tube-type rear axle in 1967. This unit was substantially stronger being, like the later gearbox, designed for the three-litre MGC. All MGBs used the tube-type axle from 1968. Brakes: All MGBs were fitted with solid (non-ventilated) disc brakes on the front with drum brakes on the rear. The front brake calipers were manufactured by Girling and used two pistons per caliper. The brake system on the MGB GT was the same as the Roadster with the exception of slightly larger rear brake cylinders. A single-circuit hydraulic system was used before 1968 when dual-circuit (separate front and rear systems) were installed on all MGBs to comply with US regulations. Servo assistance (power brakes) was not standard until 1975. Many modern and contemporary testers have commented on the very heavy brake pedal pressure needed to stop the non-servo assisted cars. Electrical system: The MGB initially had an extremely simple electrical system. Dash-mounted toggle switches controlled the lights, ventilation fan, and wipers with only the direction indicators being mounted on a stalk on the steering column. The ignition switch was also mounted on the dash. Like the MGA, the MGB utilized two 6-volt batteries wired in series to give a 12-volt positive earth configuration. The batteries were placed under a scuttle panel behind the seats making access a bit of a challenge but the location gave excellent weight distribution and thus improved handling. The charging system used a Lucas dynamo. Later MGBs had considerable changes to the electrical system including the use of a single twelve-volt battery, a change from positive to negative earth, safety-type toggle switches, an alternator in place of the dynamo, additional warning lights and buzzers, and having most common functions moved to steering column stalks. MGB Roadster | engine = I4 | length = rubber bumper version | width = | height = rubber bumper version | wheelbase = }} The roadster was the first of the MGB range to be produced. The body was a pure two-seater but a small rear seat was a rare option at one point. By making better use of space the MGB was able to offer more passenger and luggage accommodation than the earlier MGA while being 3 inches (75 mm) shorter overall. The suspension was also softer, giving a smoother ride, and the larger engine gave a slightly higher top speed. The four-speed gearbox was an uprated version of the one used in the MGA with an optional (electrically activated) overdrive transmission. Wheel diameter dropped from 15 to . Mark II In late 1967, sufficient changes were introduced for the factory to define a Mark II model. Changes included synchromesh on all 4 gears with revised ratios, an optional Borg-Warner automatic gearbox (except in the US), a new rear axle and an alternator in place of the dynamo with a change to a negative earth system. To accommodate the new gearboxes there were significant changes to the sheet metal in the floorpan, and a new flat-topped transmission tunnel. All models are rear-wheel drive. To meet US safety regulations, later North American tourers got three windscreen wipers instead of just two (to sweep the required percentage of the glass), and also received a plastic and foam rubber covered "safety" dashboard, dubbed the "Abingdon pillow". Other markets continued with the steel dashboard. Rubery Owen ROstyle wheels were introduced to replace the previous pressed steel versions in 1969 and reclining seats were standardized in 1970. 1971 also saw a new front grille, recessed, in black aluminium. The more traditional-looking polished grille returned in 1972 with a black "honeycomb" insert. 1970 saw split rear bumpers with the number-plate in between, 1971 returned to the earlier five-piece style. Mark III Further changes in 1972 brought about the Mark III. The main changes were to the interior with a new fascia. To meet impact regulations, 1974 1/4 US models saw the chrome bumper over-riders replaced with oversized rubber ones, nicknamed "Sabrinas" after the well-endowed British actress. In the second half of 1974 the chrome bumpers were replaced altogether. A new, steel-reinforced black rubber bumper at the front incorporated the grille area as well, giving a major restyling to the B's nose, and a matching rear bumper completed the change. These are 1974 1/2 models. New US headlight height regulations also meant that the headlamps were now too low. Rather than redesign the front of the car, British Leyland raised the car's suspension by . This, in combination with the new, far heavier bumpers resulted in significantly poorer handling. For the 1975 model year only, the front anti-roll bar was deleted as a cost-saving measure (though still available as an option). The damage done by the British Leyland response to US legislation was partially alleviated by revisions to the suspension geometry in 1977, when a rear anti-roll bar was made standard equipment on all models. US emissions regulations also reduced horsepower. The last MGB Roadster off the production line at Abingdon returned to Abingdon County Hall Museum on 1 December 2011 with the help of British Motor Heritage. It was lifted up 30 feet through a first floor window of the Grade I listed building with inches to spare and now forms part of the collection on display in the main gallery. Work on a successor for the MGB had been undertaken as long ago as 1968, but British Leyland had pulled the plug on that project by the end of 1970. When the Abingdon factory finally closed in the autumn of 1980, British Leyland did not replace it. Aston Martin expressed an interest in buying the Abingdon plant and continuing MGB production there. The consortia of businessmen behind the proposal commissioned William Towns to design an updated MGB, which was propoduced at Newport Pagnell in six days, ready for the publicity presentation. However, rejected outright by BL, this project failed to materialise. MGB GT I4 | length = rubber bumper version | width = | height = rubber bumper version | wheelbase = }} The fixed-roof MGB GT was introduced in October 1965. Production continued until 1980, though export to the US ceased in 1974. The MGB GT sported a ground-breaking greenhouse designed by Pininfarina and launched the sporty "hatchback" style. By combining the sloping rear window with the rear deck lid, the B GT offered the utility of a station wagon while retaining the style and shape of a coupe. This new configuration was a 2+2 design with a right-angled rear bench seat and far more luggage space than in the roadster. Relatively few components differed, although the MGB GT did receive different suspension springs and anti-roll bars and a different windscreen which was more easily and inexpensively serviceable. Early prototypes such as the MGB Berlinette produced by the Belgian coach builder Jacques Coune utilized a raised windscreen in order to accommodate the fastback. Acceleration of the GT was slightly slower than that of the roadster due to its increased weight. Top speed improved by 5 mph (8 km/h) to 105 mph (170 km/h) due to better aerodynamics. MGB GT V8 Rover V8 }} MG began offering the MGB GT V8 in 1973 utilising the ubiquitous aluminium-block 3528 cc Rover V8 engine, first fitted to the Rover P5B. This engine had been used in the A-body platform Buick Special and Oldsmobile F-85 and was the lightest mass-production V8 in the world, with a dry weight of only , and was about lighter than its 4-cylinder counterpart by the MOWOG (Morris-Wolseley Garages) foundry. Some improvements were made by MG-Rover, and the engine found a long-lived niche in the British motor industry. These cars were similar to those already being produced in significant volume by tuner Ken Costello. MG even contracted Costello to build them a prototype MGB GT V8. However, the powerful engine used by Costello for his conversions was replaced for production by MG with a more modestly tuned version producing only 137 bhp(102 kW) at 5000 rpm. But of torque helped it hit in around 8 seconds, and go on to a respectable top speed. By virtue of its aluminium cylinder block and heads, the Rover V8 engine actually weighed approximately forty pounds less than MG's iron four-cylinder. Unlike the MGC, the V8 that provided the MGB GT V8's increased power and torque did not require significant chassis changes nor sacrifice handling. Only GT versions of the V8-powered MGB were produced by the factory. Production ended in 1976. MG never attempted to export the MGB GT V8 to the United States. They chose not to develop a left-hand-drive version or to seek US air pollution emission certification of the MGB GT V8, although the Rover V8 engine was offered in US-bound Rover models throughout the same period and beyond. British Leyland Motor Corporation management cited insufficient production capacity to support anticipated demand for the V8 engine in MGB GT, so they priced the MGB GT V8 high. The MGB GT V8 was very warmly received by the automotive press, but British Leyland Motor Corporation was reportedly concerned that the MGB GT V8 would overshadow their other products, including the more expensive Triumph Stag. MGC C-Series I6 }} The MGC was a 2912 cc, straight-6 version of the MGB sold from 1967 and produced through to August 1969 with some sales running on into 1970. The car was given the model code ADO52. It was intended as a replacement for the Austin-Healey 3000 which would have been ADO51 but in that form, never got beyond the design proposal stage. The first engine to be considered was an Australian-designed six-cylinder version of the BMC B-Series but the production versions used a 7 main bearing development of the Morris Engines designed C-Series that was also to be used for the new Austin 3-litre 4-door saloon. In the twin SU carburettor form used in the MGC the engine produced at 5250 rpm. The body shell needed considerable revision around the engine bay and to the floor pan, but externally the only differences were a distinctive bonnet bulge to accommodate the relocated radiator and a teardrop for carburettor clearance. It had different brakes from the MGB, 15 inch wheels, a lower geared rack and pinion and special torsion bar suspension with telescopic dampers. Like the MGB, it was available as a coupé (GT) and roadster. An overdrive gearbox or three-speed automatic gearbox were available as options. The car was capable of 120 mph (193 km/h) and a 0–60 mph time of 10.0 seconds. The heavy engine (209 lb heavier than the 1798 cc MGB engine) and new suspension changed the vehicle's handling, and it received a very mixed response in the automotive press. The MGC was cancelled in 1969 after less than two years of production. Today the car is considered very collectible and the main causes of the poor reputation relating to handling have in the main been overcome by better tyres and subtle modification of suspension settings. Simple tuning of the under-developed straight six is also common and simple modifications to head, exhaust and cam release approx 30 percent more power and torque than original. At the time of the car's launch the manufacturers stated that the Austin-Healey 3000 would continue to be offered as a parallel model, but priced on the domestic market at £1,126 at a time when the MGC came with a recommended sticker price of only £1,102. The statement seems to have been made in order to avoid having to sell off slow moving inventory cars at second hand prices, since Austin-Healey 3000 production ended with the launch of the MG MGC in 1967. In 1967 HRH Prince Charles took delivery of an MGC GT (SGY 766F), which he passed down to Prince William 30 years later. RV8 Rover V8 }} Interest in small roadsters increased following the launch of the Mazda MX-5 in 1989, and MG (then owned by Rover Group) capitalised on this in 1992 by producing new body panels to create an updated version of the old car. The suspension was only slightly updated, sharing the old leaf spring rear of the MGB. The boot lid and doors were shared with the original car, as were the rear drum brakes. However, the engine was the 3.9-litre version of the respected aluminium Rover V8, previously used in the MGB GT V8. A limited-slip differential was also fitted. The interior was built to luxury standards, featuring veneered burr elm woodwork and Connolly Leather. Performance was good, with 190 bhp (142 kW) at 4,750 rpm and 0–60 mph (96 km/h) in 5.9 seconds. Largely due to the rear drum brakes and rear leaf springs (perceived to be too old fashioned for a modern performance car), the RV8 was not popular with road testers at the time. However, this did not prevent the RV8 from being a moderate sales success, and it paved the way for the introduction of the modern MGF a few years later. It also capitalised on an appreciation for British products in Japan. A large proportion of the limited MG RV8 production went to that country – 1579 of the 2000 produced. Australian assembly The MGB was assembled in Australia from 1963 to 1972,MG MGB Roadster (1963 - 1972) www.carpoint.com.au. Retrieved on 21 December 2011 during which time approximately 9,000 were sold. The cars were assembled from complete knock down kits shipped from England. The arrangement ended in 1972 when the government issued a requirement that to enjoy favourable tariff treatment locally produced cars should feature 85% local content. At the time the local content of the Australian assembled MGBs was evaluated as just 45 percent. Motor sport Specially tuned MGBs (including some made out of aluminium) were successful in international road competition events, scoring a Grand Touring category victory in the 1965 Monte Carlo Rally.Readers' guide to who won at Monte Carlo, British Motor Corporation advertisement, Life Magazine, 14 February 1964, page 81 Retrieved from books.google.com.au on 22 December 2011 Circuit racing wins included the Guards 1000 miles race at Brands Hatch in 1965 and the 84-hour Marathon de la Route at the Nürburgring in 1966.ML Twite, The World's Racing Cars, Fourth Edition, 1970, page 104 MGBs also won the GT Category in the 1966 Targa Florio, the 1966 Spa 1000 and the 1967 Spa 1000. Preservation These are a popular car with many restored examples about, supported by a number of specialist suppliers and restorers. Many example were simply parked in garage and left in the 1980s when they went out of fashion or owners got a family and they became impractical and got left in the garge. A lot of current owners are 'reliving' their youth and can afford to buy restored examples that are beer than the old banger they had originally, while others are painstakingly restoring their own example recovered from the shed. ;Surviving examples: * - Seen at Renishaw Hall Classic Car Show Gallery File:1966 MGB GT.jpg|1966 MGB GT File:MGB Roadster 1972 Interior left.jpg|MGB Roadster 1972 Interior File:MGB Roadster 1973.JPG|MGB Roadster 1973 UK File:1973 MGB 'Tourer' fitted with 'Factory Hardtop'.jpg|1973 MGB 'Tourer' fitted with 'Factory Hardtop' File:1975 MG B convertible.jpg|North American "rubber bumper" MG MGB (1975) File:MG RV8.jpg|MG RV8 rear File:MGB Front Suspension.jpg|1965 MGB Front Suspension Assembly File:MGB Engine Bay.jpg|1965 MGB Modified Engine Bay MG_?_-_VFO_912_at_Renishaw_2011_-_IMG_8292.JPG|VFO 912 at Rensihaw Hall Classic Car show See also * List of British car marques * List of Vehicles by registration number References/sources References * * * * * * * * External links B Category:Roadsters Category:Coupes Category:Rear-wheel-drive vehicles Category:Vehicles introduced in 1962 Category:1960s automobiles Category:1970s automobiles Category:1980s automobiles Category:1990s automobiles Category:Pininfarina Category:Cars assembled in Australia